Arc-lamp electrode.



UNITED STATES PATENT oirEIcE.l

inorr, or ntaicnwc'oii, omo, Assieivon. To Narioiran cannon courait?, ,i

or cLEvEnaND, eine, s. consommer: or NEw JEitsEY.

Ec-miur EL'EoTnoDE.

'WILLIM R.

pecincation of Letters Patent.

Patented July at, i915.

No Drawing. Original application nled June 6, 1918, Serial No. 772,180.Divided and this application filed September as, 1814.

To all whom 'it may concern.'

Be it known that I, Wmniain R. Mo'ri, a

citizen of the United `States residing at Lakewood in the county oi'cduyahoga and State of hio, have invented a certain new and usefulImprovement in Arc-Lamp Electrodes, of which the following is a full,clear, and exact description. My invention relates to are lightelectrades containing materials for producing a flamin or luminous arc,'and is more particular y adapted to those of a carbonaceous nature. y

y This ap lication isa division ofiny apglication Serial No. 772,180,led June 6, 18.

l(llne object of my invention is to use matcrials in an arc lampelectrode of the Haming type that will increase the candle power,

. and at the same time reduce or eliminate slugging on the positiveelectrode which as a ru e Acontains the aming material.

Another object of my inventionis to provide a material that can be usedin the negative electrode to prevent slag formations thereon. n

, Another objectof myinvention is to provide the particles of the amingmaterial" with a non-hygrosco ic coating or incrustation to protect themrom moisture. f

Other objects will appear in the appended description.

Flaming arc electrodes consist of a body of ca rbon with naming materialsuch as the fluoride of calcium, rare-earths, etc., and arc t su portinmaterials such as potassium and so ium4 sa ts. Most of the materialsused with the carbon produce more or less slag. My invention isarticularly adapted for use in solid electro es' havingv suolil a aininmixture, though not necessarily limite thereto.` It is not new to usesilica, silicates and such compoundsoi silicon as carborundum, ctc. inlamp electrodes. However, the silica 45. used is obtained from thenatural cr stelline .product which has very objections le feaures. v

1n flaming electrodes, thenatural form of -'silica.icausesninsulatingbuttons ci .slag to 5 0 form on the ends of Ielectrodes which obscurelthe light and ultimately cause the arc of the air coul 'reach them.

Serial No. 868,881.

to be extinguished. Afterv having been exsilica, when used with. -iiaminmixes in the Y place of the natural ycrstalline silica, silicon,carborundum, or t e silicates oi soditim, potassium and calcium,increases the candle power very considerablyi ai'd reduces the sluggingtendencies to such 'an extent that' they can be aid to be practicallyeliminated. I cannot say beyondJ question exactly why the such-radicallyi'erent results, but vI believe it is on account of the extreme nenessof the particles and the increased'chemical reaction that takes placethe arc.

Certain types of iiaming electrodes give excellent results as far asight eiiiciency 1s concerned, but on account of containing certaincalcium compounds and carbonates, the bakin in the furnace results inthe forma; tion o calcium oxid. Calcium onid or lime will absorbmoisture from the air to produce calcium hdroxid and finally calciumcarbonate, whic disintegration of' the electrode. 1 iave knownelectrodes strong and rigid in all respects to be reduced to owder in ushort time after bein 'stored w ere the moisture I have iound that thisdisintegration ca n be practically eliminated b incorporating preciitated lsilica in the e ectrode containing car onates and compounds ofcalcium.

Silica could be pre ared in any of thev wa, s well known to c emists,such asprecipitating it from a solution of a silicate frequently causescom lete withA` some acid such as nitric, sulfuric or` hydrochloric. Thesilicamay also be pre'- ared by oxidizing silicon vapor b bring ingit incontact with the oxygen o the air.-

he electrode (in usual practice the positive electrodelmay be made up cicarbon and various kinds of aming materials with which is incorporatedthe precipitated silica.

The latter has its advantages when used in any kind of a carbonaceousflaming mixture, e

but as a typical example of, the electrode Acomposition,v the followingmay be given:

vThese materials may be homogeneously mixed with carbon to form a solidelectrode or they maybe incorporated partly or entirely 1n 'the core ofthe electrode. I

In forming the oxids of tungsten and silicon, I find it advantageous` toprecipitate both simultaneously from a mixture of soluble silicates andtungstates bythe addition of an acid as previously described. This givesa very intimate mixture of the two oxids which is a desirable` feature.

In direct. current flaming lamps of the carbonaceous type, the flamingmaterial is mostly in the positive electrode, the negative electrodecontaining little or no materials that enhance the flaming property ofthe arc, except in that Vtype of lamp in which the stub from the burnedout positiveelectrode is placed in the negative holder to constitute thenegative electrode. If an electrode is composed of various materials insuch proportions as to reduce slagging when lit acts as a positiveelectrode, it is liable to slag very badly when the stub is used as 'anegative electrode. In` all cases, it is extremely diiiicult to preventslag formations on a negative electrode, and as far as I am aware, thereis no material or combination of materials so eicient in eliminatingslag on'the negative electrode as the precipitated silica, constituting'one of the objects of my invention. This materiahwhen put in a negativeelectrode, causes it to burn with a clean point, and very little troublein slagging is experienced. My invention, therefore, is especiallyuseful in those types of flaming lamps in whichthe positive stub is usedas a negative, since the precipitated silica contained therein acts alsoto eliminate slag when it is used as the negative. In other words, myimproved combination of materials tends to make a universal electrodefor direct current lamps. Boric oxid, aluminum oxid and chromic oxidhave somewhat the same effectas the silica when Vused in negativeelectrodes, but in a much less deee. grTungsten compounds, one of whichhas been previously mentioned, have been found to be a valuableconstituent of lamp electrodes, as tunsten forms many complex compoundswith numerous other elements, and, inasmuch as the efficiency of the arcseems to depend upon the number of possible compounds that can be formedtherein, it adds greatly to the efficiency. However, on account of thecomparatively high cost of tungsten, I have experimented with othermaterials with lthe idea of decreasing/'fthe amount of tungstennecessary, or eliminating it altogether. I have found that the tungsticoxid can be replaced by phosphoboric compounds in combination with othermaterials such as the precipitated silica previously described. Thesubstitute materials produce substantially as good a light as thetungstic oxid, and at the same time, eliminate the slag formationsalmost altogether.

I have obtained electrodes that burn with high candle power andsubstantially no slag by incorporating the phospho-boric compounds incombination with silica in a flamlng mixture. The silica is preferablyused in the form of a precipitate for the reasons previously given.After the' silica is preclpitated, it is placed in a solution of boricand phosphoric acids and evaporated to dryness. I also prefer to heatthe residue to a low red heat. This process causes a phospho-boricincrustation to be formed on the small' particles of the silica whichprotects them from moisture, since the phospho-boric compound isnon-hygroscopic and insoluble. This is a very important feature, as somesubstances produce an ellicient light but are hygroscopic to such anextent as to cause disintegration of the electrode as previouslyexplained.

The chemical composition ofthe coating taining these last mentionedmaterials, the

following may be given, though the proportions can be changed withoutentirely eliminating the desirable features produced thereby. Coke orother carbon, 55 partsgcalcium or rare-earth liuorids, 32 parts;carbonates of sodium and potassium, five partsj silica and phospho-boriccompound six parts. To this also may be added one part fused borax andone part barium sulfate.

The process can also be used to apply a coating or incrustation onmaterials other than silica. It is not new to use phosphoboric compoundsin electrodes per se, but I believe I am the rst to use such material asa coat around the particles of another -material to be incorporated in alamp electrode. I also lay claim to the broad idea of applying anincrustation to such particles and instead of using phospho-boriccompounds I may use other substances, sodium sulfate and potassiumchlorid being given by way of example.

In my original, application previously mentioned, of which this is adivision, the claims relate to the use of precipitated silica in an arclamp electrode, and in another copending divisional application, SerialNo.

863,882, filed September 28, 1914, claims are drawn to an arc lamphaving electrodes embodying the invention.

Having described my invention, what I claim is:

l. An arc lamp electrode containing 11am ing materials the particles ofwhich are incrusted with a protecting coating.

2. An arc lamp electrode containing par-` ticles incrusted with aphospho-'boric compound.

3. An arc lamp electrode containing precipitated silica in a linelydivided state, the particles being incrusted with a protecting coat.

4. An arc lamp electrode containing precipitated silica, .the-particlesof. which are incrusted with a coating of a phospho-boric compound.

- 5. The method of preparing materials for Vflaming arcs, which consistsin evaporating to dryness said materials in a pulverulent state in asolution containing compounds of boron and phosphorus.

6. The method of preparing materials for 'flaming arcs, which consists1n precipitating -oxids from solution and evaporating the precipitate todryness in a solution containing compounds of boron and phosphorus.

In testimony whereof, I hereunto affix my signature.

'WILLIAM R. MOTT. Witnesses P. P. BETHEA, H. G. GRovER.

